Internal combustion engine



A ril 5, 1966 c. R. CURTISS 3,244,155.

INTERNAL COMBUSTION ENGINE Filed Sept. 20, 1963 s Sheets-Sheet 1 /4 FIG. I

INVENTOR.

CHARLES R. CURTISS BY FULWIDER, PATTON, 5 2 RIEBER, LEE 8. UTECHT 7 ATTORNEYS April 1966 c. R. CURTISS 3,244,156

INTERNAL COMBUSTION ENGINE Filed Sept. 20, 1963 INVENTOR. CHARLES R. CURTISS BY FULWIDER, PATTON,

RIEBER, LEE 8' UTECHT ATTORNEYS 5 Sheets-Sheet 2 April 1966 c. R. CURTISS 3,244,156

INTERNAL COMBUSTION ENGINE Filed Sept. 20, 1963 3 Sheets-Sheet 5 20 M2 /zz M4 1.2 mo 20 M8 4 M8 a8 //0 I a I //6 4.., //a

INVENTOR. CHARLES R. CURTISS BY FULWIDE PATTON,

RIEBER, 8(UTECHT AT TOR N EYS United States Patent Office 3,244,156 Patented Apr. 5,

3,244,156 INTERNAL COMBUSTION ENGINE Charles R. Curtiss, Seaside, Calif, assignor of one-half to Jerry Witcher, Monterey, Calif. Filed Sept. 20, 1963, Ser. No. 310,316 4 Claims. (6i. 123-11) The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine wherein the pistons thereof rotate in a common annular chamber.

Internal combustion engines of this general class are known in the prior art, the United States Letters Patent No. 1,212,649, issued January 16, 1917, to M. A. Krikorian, and entitled, Rotary Engine, being exemplary in this regard. In this type of engine a compound rotor is utilized which is constituted by a pair of piston carriers which are each provided with a plurality of circumferentially spaced pistons for rotation within a common annular chamber. The pistons of one carrier serve as driven vanes while the pistons of the other carrier act as substantially fixed abutments, the arrangement being reversed after the power stroke, with the pistons of the first carrier acting as the abutments and those of the second carrier acting as the driven vanes. For this purpose, the pistons of one carrier are arranged adjacent the pistons of the other carrier in alternating relationship, the carriers being alternately driven in the same direction to effect rotation of a centrally located drive shaft.

The engine of the present invention differs from those of the prior art in a number of important respects, but primarily in the means by which the pair of piston carriers transmit their rotation to the drive shaft. In the prior art engines, the piston carriers are alternately fixed to the drive shaft by systems productive of unwanted shock, vibration, premature wearing of the engine components, and loss of operating effi'ciency. Moreover, prior art engines of this type have also been characterized by unsatisfactory means for temporarily locking the piston carriers in alternation against movement relative to the piston casing, as first one and then the other of the carriers are driven by the motive fluid or expanding gases, and are further characterized by unsatisfactory means for positioning the carriers relative to each other and for cushioning their interaction.

Accordingly, it is an object of the present invention to provide an internal combustion engine including a casing having an annular chamber, a drive shaft rotatably carried by the casing along the axis thereof, and a pair of piston carriers alternately driven by combustion occurring between the alternating vanes or pistons thereof for alternately driving the carriers in the same direction, and wherein the alternate rotation of one of the piston carriers ahead of the other is smoothly and efiiciently transmitted to the drive shaft substantially without shock and vibration.

Another object of the invention is to provide an internal combustion engine of the aforementioned character wherein the pair of piston carriers are coupled to the drive shaft through a transmission disk which is fixed to the drive shaft, rotatable with the piston carriers, and additionally rotatable in advance of one of the carriers by the differential rotation of the carriers. The transmission disk is adapted to freely rotate with the pair of piston carriers when such carriers are rotating at the same speed, but more rapid rotation of the carrier passing through a power stroke advances the transmission disk beyond the relative position of the more slowly rotating piston carrier.

A further object of the invention is the provision of an internal combustion engine of the aforementioned character wherein positioning means are interposed between the pair of piston carriers for maintaining the pistons of the piston carriers in proper juxtaposition relative to each other for establishment of intake, compression, combustion, and exhaust strokes of the pistons thereof, the positioning means also affording a means for cushioning the interaction between the pair of piston carriers.

A further object of the invention is to provide an internal combustion engine of the aforementioned character in which couplings are provided between the piston carriers and the casing to prevent substantial slowing of one carrier during the interval when rotation of the other carrier is being speeded by reason of passage of the pistons thereof through a power stroke, whereby the differential rotation between the carriers may be utilized for driving an output shaft.

A further object of the invention is the provision of an internal combustion engine of the aforementioned character wherein the pair of piston carriers, the casing within which the carrier pistons rotate, and the associated components comprise a power pod which is adapted for mounting upon an output shaft with other such pods to multiply the shaft output horsepower as desired.

Yet another object of the invention is to provide an internal combustion engine of the aforementioned character in which the intake and exhaust ports are substantially always open and are absent sleeve, poppet, and other similar closure valves, and in which the ignition system is not timed according to the piston positions but is constantly operative to ignite a charge adjacent an ignition plug of the system.

A further object of the invention is to provide an internal combustion engine of the aforementioned char acter which is relatively inexpensive to manufacture, operate, and maintain, and which is characterized by improved efiiciency of operation, particularly in that substantially all moving parts are characterized by a rotary rather than a reciprocating motion.

Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of an internal combustion engine according to the present invention, a portion thereof being shown in cross-section;

FIG. 2 is a view, on a reduced scale, taken along the line 22 of FIG. 1;

FIG. 3 is an enlarged detail view taken along the line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 3, but showing the particular direction of rotation of one of the transmission rnove- FIG. 7 is a view taken along the line 77 of FIG. 1,

and in which certain of the pistons of one carrier are shown in their locations just prior to a combustion stroke;

FIG. 8 is a view similar to FIG. 7, but showing the pistons of said one carrier upon completion of the combustion stroke;

FIG. 9 is a view taken along the line 9--9 of FIG. 1;

FIG. It) is a detail view on an enlarged scale, taken along the line 1010 of FIG. 1;

FIG. 11 is a detail view on an enlarged scale, taken along the line 11-11 of FIG. 7; and

FIG. 12 is a detail view on an enlarged scale, taken along the line 12-12 of FIG. 7.

Referring now to the drawings, and particularly to r 3 FIGS. 1 and 2, there is illustrated an internal combustion engine according to the present invention and which is adapted to be mounted upon an output shaft 12 for rotation thereof. The engine 10 may, if desired, constitute one pod of a plurality of pods mounted upon the output shaft 12, the cumulative effect of the plurality of pods being to increase the power applied .to the output shaft 12 as desired.

The engine 10 comprises, generally, a casing 14 having an annular chamber 16 which is generally circular in transverse cross-section; a pair of rotor sections or piston carriers 18 and 20 having a plurality of integrally mounted, hollow, generally cylindrical pistons 22 and 24, respectively, which closely fit and rotate within the chamber 16; a pair of rotation control means 26 and 28 interposed between the casing 14 and the carriers 18 and 20, respectively, which permit rotation of the carriers in an output direction and constrain the carriers against rotation in the opposite direction; transmission means 30 fixed to the output shaft 12 and interposed between the carriers 18 and 20 for translating the differential rotation of the carriers 18 and 20 into an output rotation of the shaft 12; and positioning means 32 interposed between and in engagement with the piston carriers 18 and 2th for proper intake, compression, combustion, and exhaust. In addition, a suitable cooling system (not shown) is preferably utilized to carry away excessive heat from the engine, and may constitute suitable cooling jackets disposed adjacent the casing and through which cooling fluid is circulated, as will be apparent to those skilled in the art.

a The casing 14 includes a pair of substantially symmetrical sections 34 and 36 having abutting radial flanges 38 and 40 between which is positioned an annular sealing gasket'42, the flanges 38 and 48 being secured together with the gasket between them by a plurality of circumferentially spaced bolt and nut assemblies 44 located in registering openings provided in the flanges 38 and 40. The confronting inner surfaces of the casing sections 34 and 36 define the chamber 16 adjacent the flanges 38 and 40; a larger, annular central enclosure 46 adjacent the shaft 12; and an annular sealing passage 48 affording communication between the chamber 16 and the central enclosure 46, the carriers 18 and 20, exclusive of the pistons thereof, rotating within the chamber 16 and the enclosure 46. i

As best viewed in FIG. 5, the casing 14 also includes four circumferentially equally spaced inlet ports 50 which are coupled with an intake manifold (not shown) of a usual and conventional fuel supply system which includes a suitable fuel supply and fuel carburetion or injection apparatus. The operation of such systems is well known to those skilled in the art, and a detailed description of such a system is omitted for brevity.

The casing 14 also includes four exhaust ports 52, as best viewed in FIGS. 1 and 2, for carryingaway the spent or exhaust gases produced in the chamber 16 during operation of the engine 10, the ports 52 being connected by exhaust manifold conduits 54 to an exhaust manifold 56 which is connected to a centrifugal exhaust blower 58 and rigidly bolted to the casing 14. The blower 58 includes a hollow housing 60 which is rigidly bolted or otherwise secured to the exhaust manifold 56, and a bladed impeller 62 is rotatable within the housing 60 for drawing exhaust gases out of the exhaust manifold 56 for discharge from the housing 60 and into an exhaust pipe 64 which opens to the atmosphere.

A stub shaft 66 is rotatably carried by the blower housing 60 and fixedly mounts the exhaust impeller 62 at one extremity, by means of a Woodrutf key 68 or the like, and a spur or driven gear 70 at the opposite extremity by a key 72. The driven gear 72 meshes with a larger gear 74 which is fixed to the output shaft 12 by a key 76 whereby rotation of the output shaft 12 drives the impeller 62 for exhausting spent combustion gases from the chamber 16, as will be more particularly described hereinafter.

The casing 14 also includes four threaded openings for receiving a corresponding plurality of ignition plugs 78 of either the continuously sparking or glow type to provide constant ignition of combustible mixtures in proximity therewith. The ignition plugs 78 are connected to a suitable ignition system (not shown) effective to spark or heat the ignition plug electrodes to a temperature sufficient to ignite the adjacent charge in the chamber 16. Thus, the ignition system is not required to be timed in relation to the orientation of the pistons 22 and 24, but is effective at all times to ignite any combustible fuel charge surrounding the ignition plug electrodes. Suitable electrical or ignition systems to provide this result will be immediately apparent to those skilled in the art, and therefore a detailed description of an exemplary system is omitted for brevity.

The rotational paths described by the pistons during their travel through the chamber 16 are of equal diameters so that the pistons are freely rotatably slidablt along the surfaces of the casing defining the chamber 16. The pistons are each generally cylindrical in configuration, but slightly arcuately contoured along the axis of the chamber 16 to facilitate rotation through the chamber. Each of the carriers 18 and 20 preferably includes eight pistons, the pistons of one carrier being arranged in alternating relationship with the pistons of the other carrier whereby the space within the chamber 16 between each pair of the pistons 22 constitutes a piston chamber within which one of the pistons 24 of the other carrier is operative, and, conversely, the space between adjacent pistons 24 constitutes a piston chamber for a piston 22, depending upon which of the carriers is undergoing a power stroke. Moreover, the piston carriers are laterally offset to permit each to rotate past the other without interference, even though the pistons of the carriers are aligned for rotation in the common chamber 16.

Each of the piston carriers 18 and 28 includes a central opening for receiving an annular outer race 80 which supports a plurality of needle bearings 82 in engagement with the periphery of the output shaft 12. This affords a substantially frictionless engagement between the carriers and the shaft 12 so that the carriers are freely rotatable relative to the output shaft 12.

In order to prevent undesired leakage of gases from the chamber 16, other than through the exhaust ports 52, each of the pistons 22 and 24 is provided with a pair 'of piston ring assemblies 84, as best viewed in FIGS. 7, 8, 11, and 12. Each piston ring assembly includes an annular piston ring 88 which fits within a complemental annular groove provided therefor in the associated piston. The rings 88 are freely sli-dable upon the walls defining the chamber 16, each ring extending about the complete periphery of the associated piston.

Each ring 88 includes a flange 90 at one extremity which extends radially inwardly between the portions of the carriers 18 and 28 immediately adjacent the pistons. The opposite extremity of the ring 88 pivotally mounts a sealing element 92 which lies exteriorly of the associated piston carrier and in substantially parallel relationship with the confronting flange 90, the pivotal mounting of the element 92 facilitating mounting of the piston ring upon the associated piston.

The piston rings 88 thus are arranged to substantially prevent leakage of gases past the pistons along the axis of the annular chamber 16. Gas leakage radially inwardly is also substantially prevented by a sealing ring arrangement constituted by an annular, circumferentially oriented sealing ring set 94 carried within a complemental annular groove provided therefor in the piston carrier 18, the sealing ring set 94 being in slidable engagement with the adjacent wall of the casing section 34 which defines the sealing passage 48.

Each sealing ring set 94 is preferably constituted of a solid split outer ring and an underlying resilient ring to resiliently bias the outer ring into engagement with the adjacent casing section-34. An identical sealing ring set 96 is carried within a complemental groove provided therefor in that side of the piston carrier 20 adjacent the carrier 18 so that the outer solid-ring of the set 96 is in sliding engagement with the adjacent surface of the carrier 18. In addition, the carrier 20 mounts an identical sealing ring set 98 in a complemental groove provided therefor on the opposite side of the carrier 20, the solid ring portion of the set 98 being arranged in slidable engagement with the adjacent wall of the casing section 36 which defines the sealing passage 48. With this arrangement, the sealing ring sets 94, 96, and 8substantially prevent undesired leakage of gases radially inwardly from the, chamber 16, during operation of the engine 10.

As previously indicated, each of the piston carriers 18 and 20' is rotatable in one direction, as indicated by the arrow 100 in FIG. 7, but is constrained against rotation in the opposite direction by the rotation control means 26 and, 28, respectively. As best illustrated in FIGS. 1, 7; 8, and 10, each rotation control means. comprises a plurality of dogs. or controllers 102 secured to the corresponding piston carrier upon the outer face thereof, the controllers 102 being equally spaced circumferentially about the pistoncarrier. Each controller 102 includes a radially outwardly located pillow or bearing block 104 and a radially inwardly located pillow or hearing. block 106 which are secured by suitable bolts. 108 to the corresponding piston carrier. The controller 102* also includes a radially inwardly tapered gear 110 located intermediate the blocks 104 and 106, and a shaft 112rotatably mounting the gear 110 to the blocks 104 and 106.

The exemplary controller 102 shown mounted to the piston carrier 20 in FIG. rotates with the carrier 20 in the direction of the arrow 100, the gear 110 meshing with a circumferentially disposed gear rack 114 which is formed in the adjacent interior wall of the casing section 36, as best viewed in FIG. 1. Rotation of the carrier 20 in the direction of the arrow 100 is permitted by the controller 102 since the gear 110 is free to rotate in the direction of the arrow 116. This result is achieved by provision on the shaft 112 of external Acme threads which mate with complemental internal Acme threads provided centrally of the gear 110. The direction of the threads, as illustrated, causes the gear to rotate upon the shaft 112 radially inwardly into engagement with an enlarged collar 118 integral with the shaft 112. The gear 110, collar 118, and shaft 112 rotate together freely in the direction of the arrow 116 to permit rotation of the carrier 20 in the direction of the arrow 100.

Conversely, in the event that the carrier 20- tends to move in a direction opposite that of the arrow 100, that is, in a non-power output direction, the gear 110, is caused by the gear rack 114 to rotate in a direction opposite the direction 116 so that the gear 1102 moves radially outwardly, which brings a boss 120, located at the radially outward extremity of the gear 110, into frictional engagement with the bearing block 104. Moreover, the shaft 112 is simultaneously moved downwardly to bring the headed upper extremity 122 of the shaft 112 into. frictional engagement with an annular seat 124 provided therefor in the radially outward, face of the bearing block 104.

As will be apparent, all of the controllers 102 mounted upon the carrier 20 operate in similar fashion to permit rotation of the carrier 20 only in the direction of the arrow 100'. The controllers 102 mounted upon the carrier 18 also operate in identical fashion to permit rotation of the carrier 13 in the same direction as that of the carrier 20, but constrain or dog the carrier 18 against opposite rotation. In this manner, the carriers 18 and 20 are permitted to move only in a power output direction to rotate the output shaft 12 in the direction of the arrow 100 shown in FIG. 1.

Any rotation of one of the carriers 18 or 20 in the direction indicated by the arrow 100, and in advance of similar rotation of the other carrier, is converted by the transmission means 30 into output rotation of the output shaft 12. As best viewed in FIGS. 1, 3-5, and 9, the transmission means 30 comprises a plurality of radially inwardly tapered transmission elements or gears 126- which are equally circumferentially spaced about and rotatably mounted to a circular transmission disk 128, the disk 128 being fixedly secured to the output shaft by a pair of Woodruff keys 130. The gears 126 are rotatably carried in any suitable fashion by the disk 28, and are interposed between and meshed with a pair of confronting, circumferentially oriented gear racks 132 and 134 formed, respectively, in the confronting inwardly disposed walls of the piston carriers 18 and 20.

With this arrangement, when the carriers 18 and 20 are rotating in the direction of the arrow 100, the transmission disk 128 is rotated at the same rate, consequently rotating the output shaft 12 at that rate. However, as-

suming the carrier 18 is momentarily accelerated, as

viewed in FIG. 5, and the carrier 20 is momentarily constrained against any such momentary accelcration, as will become apparent hereinafter, the transmission gears 126 will also be momentarily carried by the gear rack 132 in the direction of the arrow 100, the gears 126 necessarily being moved in this direction because of the temporary slower rate of the gear rack 134. That is, the gears 126 climb along the gear rack 134, which is effectively stationary, by reason of the rotation of the gears by the then more rapidly rotating gear rack 132. Conversely, the opposite occurs when the piston carrier 20 is momentarily accelerated at a rate greater than that of the carrier 18, as viewed in FIG. 4, the gears 126 in this case climbing along the gear rack 132 in response to the rotation of the gears caused by the more rapidly rotating carrier 20. Thus, during alternate momentary accelerations of the carriers 18 and 20, the gears 126 experience constant reversals of rotation, depending upon which of the carriers is then being accelerated, but in all cases the momentary acceleration of the then accelerated carrier is transmitted by the gears 126 to the transmission disk 128 to effect acceleration of the output shaft 12 during each such accleration or increase of rotation of either of the carriers 18 or 20.

Referring now to FIGS. 7 and 8, the pistons 22 and 24 are shown in the positions assumed immediately upon ignition of the compressed charges in the four piston chambers. The expanding gases resulting from such ignition exert pressures against the adjacent faces of the pistons 22 and 24 which define the piston chambers, tending to move the pistons 22 in a direction opposite that indicated by the arrow 100. As previously described, such tendency is prevented by the action of the rotation control means 26, However, the momentary pressure upon the pistons 24 efiects rotation thereof in the direction of the arrow 100, which rotation is transmitted by the transmission means 30 to the output shaft In FIG. 8, the pistons 24 are illustrated in the positions assumed upon completion of the ignition or power stroke, and it is seen that the same pistons 24 have also moved through an exhaust stroke, forcing spent gases ahead of them through the exhaust ports 52. In addition, the consequent rotation of the carrier 20 effects movement through an intakestroke of each of those pistons 24 not being acted upon by the ignited and expanding gases, the fuel being sucked in through the inlet ports 50, and these same pistons also effect compression of the fuel mixture lying ahead of them. Thus, certain of the pistons 24 are moved through power strokes and exhaust strokes while others of the pistons 24 are simultaneously moved through intake strokes and compression strokes, the adjacent pistons 22 in each case serving as relatively fixed abutments.

When the pistons 24 are moved from the positions illustrated in FIG. 7 to the positions illustrated in FIG. 8, the momentary and corresponding acceleration of the F carrier 20 stores energy in the positioning means 32, the carrier 20 being slowed or braked more and more firmly as the pistons 24 reach the end of their strokes.

More particularly, the positioning means 32 includes a plurality of circumferentially arranged positioners 13-6 interposed between the confronting faces of the carriers 18 and 26). Each of the positioners 136 is constituted by a bracket 138 welded to the carrier 20, a complemental bracket 140 circumferentially spaced from the bracket 138 and welded to the carrier 18, and a spring 142 extending between and secured at its extremities to the brackets 138 and 140. With this arrangement any rotation of the carrier 20 ahead of the carrier 18 in the direction of the arrow ltltl causes compression of the plurality of springs 142, and the stored energy in the springs 142 is subsequently transmitted to the carrier 13 when the carrier 18 is next momentarily accelerated by ignition, as previously described; the carrier 20 is momentarily halted. Thus, the positioning means 32 has the effect of smoothing sudden relative accelerations and decelerations between the carriers 18 and 20, and properly orients the pistons 22 and 24 in spaced-apart relationship at all times so that proper intake of fuel, for example, can be had, particularly when the engine it) is first being started. in this regard, any suitable starting means (not shown) may be utilized, including manual cranking of the output shaft, or mechanized rotation thereof by a suitable starter motor or the like, as will be obvious. Once the engine It is started, the momentum of the rotating carriers 18 and 20 moves the pistons 22 and 24 thereof into the various positions necessary to effect intake, compression, ignition, and exhaust actions.

Thus, there has been described an internal combustion engine employing a plurality of cir-curnferentially spaced pistons rotatable within a common annular chamber, and in which the pistons are alternately accelerated to effect rotation of an output shaft through a transmission means which substantially smoothly and efficiently couples the momentarily accelerated set of pistons tothe output shaft, without undesirable shock and vibration. The engine 10 is particularly characterized by the utilization of components which are substantially all moving parts, whereby greatly improved operating efficiencies are attained.

Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. An internal combustion engine comprising:

, a casing having an annular chamber;

a drive shaft rotatably carried by said casing;

a first piston carrier and a second piston carrier mounted in adjacent relationship for rotation upon said drive shaft, each of said piston carriers including a plurality of circumferentially spaced pistons rotatable in said annular chamber, the pistons of said first carrier alternating with the pistons of said second carrier;

at first plurality of circumferentially arranged and spaced gears meshed with a first annular gear rack, said first gears and said first rack being secured between said casing and one of said carriers;

. a second plurality of circumferentially spaced gears meshed with a second annular gear rack, said second gears and said second rack being secured between said casing and the other of said carriers, each of said gears being rotatable in one direction to permit rotation of the associated carrier in one direction relative to said casing, and rotatable in the opposite direction to effect constraining engagement between said casing and said corresponding carrier to constrain said associated carrier against rotation in a direction opposite said one direction;

and transmission means coupled to said drive shaft and in engagement with said carriers, and adapted for accelerated movement in said one direction alternately by first one and then the other of said carriers.

2. An internal combustion engine comprising:

a casing having an annular chamber and a pair of circumferentially arranged and confronting gear racks;

a drive shaft rotatably carried by said casing along the axis of said chamber;

a first piston carrier and a second piston carrier mounted in adjacent relationship for rotation upon said drive shaft, each of said piston carriers includ ing a plurality of circumferentially spaced pistons rotatable in said annular chamber, the pistons ofsaidl first carrier alternating with the pistons of said second carrier;

first and second pluralities of rotation control gears engaged between, respectively, one of said gear racks and said first carrier, and between the otherof saidl Igear racks and said second carrier, and each freely rotatable upon rotation of said carriers in one direction, and constrained against rotation upon rotation of said carriers in a direction opposite said one direction;

and transmission means coupled to said drive shaft and in engagement with said carriers, and rotatable in said one direction alternately by one and then the other of said carriers, the more rapidly rotating carrier rotating said transmission means more rapidly than the more slowly rotating carrier.

3. An internal combustion engine comprising:

casing having an annular chamber;

a drive shaft rotatably carried by said casing along the axis of said chamber;

a first piston carrier and a second piston carrier mounted in adjacent relationship for rotation upon said drive shaft, each of said piston carriers including a plurality of circumferentially spaced pistons rotatable in said annular chamber, the pistons of said first carrier alternating with the pistons of said second carrier;

first and second pluralities of rotation control gears engaged between, respectively, one of said gear racks and said first carrier, and between the other of said gear racks and said second carrier, and each freely rotatable upon rotation of said carriers in one direction, and constrained against rotation upon rotation of said carriers in a direction opposite said one direction;

a plurality of positioning means interposed between said first and second carriers in circumferential orientation, each of said means including a portion fixed to one of said carriers, a portion fixed to the other of said carriers, and a spring secured to said portions and normally resiliently constraining said portions against relative movement toward and away from each other whereby the relative positions of said carriers in the absence of forces thereon are established, and whereby relative rotative movement between said carriers is resiliently cushioned by said bias means;

and transmission means coupled to said drive shaft and in engagement with said carriers, and rotatable in said one direction alternately by one and then the other of said carriers, the more rapidly rotating carrier rotating said transmission means more rapidly than the more slowly rotating carrier.

4. An internal combustion engine comprising:

a casing having an annular chamber;

a drive shaft rotatably carried by said casing along the axis of said chamber;

a first piston carrier and a second piston carrier mounted in adjacent relationship for rotation upon said drive shaft, each of said piston carriers including a plurality of circumferentially spaced pistons rotatable in said annular chamber, the pistons of said first carrier alternating with the pistons of said second carrier;

first plurality of circumferentially arranged and spaced gears meshed with a first annular gear rack, said first gears and said first rack being secured between said casing and one of said carriers;

second plurality of circumferentially spaced gears meshed with a second annular gear rack, said second gears and said second rack being secured between said casing and the other of said carriers, each of said gears being rotatable in one direction to permit rotation of the associated carrier in one direction relative to said casing, and rotatable in the opposite direction to effect constraining engagement between said casing and said corresponding carrier to constrain said associated carrier against rotation in a direction opposite said one direction;

plurality of positioning means interposed between said first and second carriers in circumferential orientation, each of said means including a portion fixed to one of said carriers, a portion fixed to the other of said carriers, and a spring secured to said portions and normally resiliently constraining said portions against relative movement toward and away from each other whereby the relative positions of said carriers in the absence of forces thereon are established, and whereby relative rotative movement between said carriers is resiliently cushioned by said bias means;

and transmission means coupled to said drive shaft and in engagement with said carriers, and rotatable in said one direction alternately by one and then the other of said carriers, the more rapidly rotating carrier rotating said transmission means more rapidly than the more slowly rotating carrier.

References Cited by the Examiner UNITED STATES PATENTS 848,845 4/1907 Paige 123--11 1,308,352 7/1919 Green 123-11 FOREIGN PATENTS 681,342 1/1930 France. 159,372 3/1921 Great Britain.

DONLEY J. STOCKING, Primary Examiner.

KARL I. ALBRECHT, Examiner. 

1. AN INTERNAL COMBUSTION ENGINE COMPRISING: A CASING HAVING AN ANNULAR CHAMBER; A DRIVE SHAFT ROTATABLY CARRIED BY SAID CASING; A FIRST PISTON CARRIER AND A SECOND PISTON CARRIER MOUNTED IN ADJACENT RELATIONSHIP FOR ROTATION UPON SAID DRIVE SHAFT, EACH OF SAID PISTON CARRIERS INCLUDING A PLURALITY OF CIRCUMFERENTIALLY SPACED PISTONS ROTATABLE IN SAID ANNULAR CHAMBER, THE PISTONS OF SAID FIRST CARRIER ALTERNATING WITH THE PISTON OF SAID SECOND CARRIER; A FIRST PLURALITY OF CIRCUMFERENTIALLY ARRANGED AND SPACED GAEARS MESHED WITH A FIRST ANNULAR GEAR RACK, SAID FIRST GEARS AND SAID FIRST RACK BEING SECURED BETWEEN SAID CASING AND ONE OF SAID CARRIERS; A SECOND PLURALITY OF CIRCUMFERENTIALLY SPACED GEARS MESHED WITH A SECOND ANNULAR GEAR RACK, SAID SECOND GEARS AND SAID SECOND RACK BEING SECURED BETWEEN SAID CASING AND THE OTHER OF SAID CARRIERS, EACH OF SAID GEARS BEING ROTATABLE IN ONE DIRECTION TO PERMIT ROTATION OF THE ASSOCIATED CARRIER IN ONE DIRECTION RELATIVE TO SAID CASING, AND ROTATABLE IN THE OPPOSITE 